An industrial robot comprises a manipulator and a control system for controlling the movements of the manipulator. Many industrial plants utilize systems comprising a control system and a plurality of manipulators, such as a multiple robot system or a system comprising one robot that cooperates with one or more external axes. The manipulators' movements are controlled by one or more programs. The control systems are also usually programmed to execute a plurality of task, performed by the manipulators.
In a typical multi-tasking system comprising at least a control system and multiple manipulators such as a multiple robot system, a system comprising one robot that cooperates with one or more external axes, or a system comprising a control system and one manipulator executes a plurality of programs. Some tasks require manual movement of manipulator in the multi-tasking system, for instance programming a manipulator. Many industrial plants utilize systems comprising a plurality of manipulators, such as a multiple robot system or a system comprising one robot that cooperates with one or more external axes. The manipulators are usually programmed to execute a plurality of tasks and the system comprises path planning means for calculating how the manipulators should move so as to be able to execute the programmed tasks. Certain tasks require two or more of the manipulators to move synchronously whereby the movement instructions in separate manipulator-programs are executed at the same time in order to coordinate the movements of the manipulators.
A manipulator is for instance a rotatable axis that for instance are arranged to rotate a work piece. Another manipulator is for instance composed of interconnected parts. The interconnected parts are for instance robot parts such as a foot, robot arms, arm housing, a wrist and/or a turn disc. Two adjoining robot parts are then connected to each other so as to be rotatable in relation to each other around an axis of rotation, or are linearly displaceable in relation to each other. That a manipulator is movable means that it is able to change its orientation and/or position. To control the relative positions of the interconnected parts, for instance in the control system a coordinate system is defined relative to the manipulator. The interconnected parts are arranged within the coordinate system, with their individual positions defined relative the coordinate system.
Today one robot is able to move with its position defined in such a coordinate system relative an extern rotating axis holding a work piece, the axis and the work piece positions also defined in the coordinate system.
A problem is when the process requires a system of more manipulators than one to work on the work piece is that displacement of one manipulator relative the other manipulators in the system, due to manual movement of the manipulator, leads to a time-consuming manual correction of the mutual positions of the manipulators in the system.